Piezoelectric bimorphs as microelectromechanical building blocks and constructions made using same

ABSTRACT

A plurality of MEMS devices that can be easily configured to impart extended ranges of rotational and/or translational motion. The MEMS devices comprise a micro-electromechanical building block including a bendable member having a first end connectable to a support structure, and a straight rigid member having a first end connected to a second end of the bendable member. In the event the bendable member is in a straight condition, the rigid member extends from the second end of the bendable member toward the support structure. Further, the bendable member has a predetermined length, and the rigid member has a length at least within a range from one half to the full predetermined length of the bendable member to allow a free end of the rigid member to undergo extended rotational and/or translational motion in response to a displacement of the bendable member. The respective MEMS devices can be employed as actuators or sensors in a variety of micro-electromechanical and micro-opto-electromechanical applications.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a 371 of PCT/US01/21641, filed Jul. 10, 2001 whichclaims benefit of provisional appln 60/217,191 filed Jul. 10, 2000 and aCIP of application Ser. No. 09/700,633 filed Nov. 16, 2000 U.S. Pat. No.6,657,764 which is a 371 PCT/US00/07075, filed Mar. 17, 2000 whichclaims benefit of provisional appln 60/124,982 filed Mar. 18, 1999.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

N/A

BACKGROUND OF THE INVENTION

The present invention relates generally to the field ofMicro-ElectroMechanical Systems (MEMS), and more specifically to MEMSdevices that can be easily configured to provide extended ranges ofrotational and/or translational motion.

MEMS devices have been widely employed as actuators or sensors invarious micro-electromechanical applications including inkjet printers,read/write heads in computer disk drives, accelerometers, and pressuresensors. More recently, MEMS devices have been employed in opticalnetworking applications including optical cross-connect modules forcontrolling switching between optical fiber input and output ports. Forexample, such optical cross-connects typically comprise two orthree-dimensional arrays of optical mirrors configured to directpluralities of beams of light from selected sets of fiber input ports toselected sets of fiber output ports. Further, conventional MEMS devicesincluded in such optical cross-connects are configured to move at leastsome of the optical mirrors in the array under computer control to bringabout a desired switching between the selected sets of fiber input andoutput ports.

MEMS devices employed in today's optical networking applications arefrequently called upon to satisfy demanding performance requirements.For example, such MEMS devices are often required to move relativelylarge structures (e.g., optical mirrors, prisms, or optical gratings)over relatively large distances with high speed and a high degree ofprecision. However, conventional MEMS devices used in optical networkingapplications typically impart only limited ranges of linear or angulardisplacement. Further, such conventional MEMS devices are typically onlycapable of causing structures to rotate about a single axis.

It would therefore be desirable to have MEMS devices that can beemployed as actuators or sensors in micro-electromechanical ormicro-opto-electromechanical applications. Such MEMS devices would beeasily configured to provide extended ranges of rotational and/ortranslational motion. It would also be desirable to have a MEMS devicethat can cause a structure such as an optical mirror to rotate aboutmore than one axis.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, a plurality of MEMS devices isprovided that can be easily configured to impart extended ranges ofrotational and/or translational motion. Benefits of the presentlydisclosed invention are achieved by providing a micro-electromechanicalbuilding block, one or more of which can be used to construct arespective MEMS device capable of moving a desired angular and/or lineardistance.

In a first embodiment, the micro-electromechanical building blockincludes at least one bendable member having a first end connectable toa support structure, and at least one straight rigid member having afirst end connected to a second end of the bendable member. In the eventthe bendable member is in a straight condition, the rigid member extendsfrom the second end of the bendable member toward the support structure.Further, the bendable member has a predetermined length, and the rigidmember has a length within a range from one half to the fullpredetermined length of the bendable member to allow a free end of therigid member to undergo extended rotational and/or translational motionin response to a displacement of the bendable member.

In a preferred embodiment, the support structure comprises a frame ofsilicon, the bendable member comprises a length of silicon havingregions with depositions providing bender or piezoelectric morphfunctions when energized with a voltage, and the rigid member comprisesa rigid silicon bar. The support structure, the bendable member, and therigid member are formed from the same silicon wafer by way of a siliconmicro-machining fabrication technique.

In further embodiments of the present invention, at least onemicro-electromechanical building block comprising at least one bendablemember connectable to at least one straight rigid member is used toconstruct respective MEMS devices capable of moving desired angularand/or linear distances.

A first MEMS device includes a first bendable member having a first endconnectable to a support structure, and a first straight rigid memberhaving a first end connected to a second end of the first bendablemember. In the event the first bendable member is in a straightcondition, the first rigid member extends toward the support structure.The first MEMS device also includes a second bendable member having afirst end connected to a second end of the first rigid member, in whichthe first and second bendable members are configured to undergorespective displacements in a same direction; and, a second straightrigid member having a first end connected to a second end of the secondbendable member. In the event the first and second bendable members arein respective straight conditions, the second rigid member extendstoward the support structure. The first and second bendable members havethe same predetermined length. Further, the first rigid member has alength equal to the predetermined length of the first and secondbendable members, and the second rigid member has a length equal to onehalf of the length of the first rigid member to allow a free end of thesecond rigid member to undergo a pure rotation in response to adisplacement of at least the first bendable member.

A second MEMS device includes a first bendable member having a first endconnectable to a support structure, and a straight rigid member having afirst end connected to a second end of the first bendable member. In theevent the first bendable member is in a straight condition, the rigidmember extends toward the support structure. The second MEMS device alsoincludes a second bendable member having a first end connected to asecond end of the rigid member. In the event the first and secondbendable members are in respective straight conditions, the secondbendable member extends away from the support structure. The first andsecond bendable members have the same predetermined length, and areconfigured to undergo respective displacements in opposite directions.Further, the rigid member has a length equal to one half of thepredetermined length of the first and second bendable members to allow afree end of the second bendable member to undergo a pure translation inresponse to a displacement of at least the first bendable member.

A third MEMS device includes a first bendable member having a first endconnectable to a support structure, and a second bendable member havinga first end connected to a second end of the first bendable member. Inthe event the first and second bendable members are in respectivestraight conditions, the second bendable member extends away from thesupport structure. The first and second bendable members have the samepredetermined length, and are configured to undergo respectivedisplacements in opposite directions to allow a free end of the secondbendable member to undergo a pure translation in response to adisplacement of at least the first bendable member.

A fourth MEMS device includes a first bendable member having a first endconnectable to a support structure, and a first straight rigid memberhaving a first end connected to a second end of the first bendablemember. In the event the first bendable member is in a straightcondition, the first rigid member extends toward the support structure.The fourth MEMS device also includes a second bendable member having afirst end connected to a second end of the first rigid member. In theevent the first and second bendable members are in respective straightconditions, the second bendable member extends toward the supportstructure. The fourth MEMS device also includes a second straight rigidmember having a first end connected to a second end of the secondbendable member. In the event the first and second bendable members arein respective straight conditions, the second rigid member extends awayfrom the support structure. The first and second bendable members havethe same predetermined length, and are configured to undergo respectivedisplacements in a same direction. Further, the first and second rigidmembers have respective lengths equal to one half of the predeterminedlength of the first and second bendable members to allow a free end ofthe second rigid member to undergo a pure translation in response to adisplacement of at least the first bendable member.

By employing at least one micro-electromechanical building block toconstruct a plurality of MEMS devices, respective MEMS devices capableof moving desired angular and/or linear distances can be easilyconfigured. Further, the respective MEMS devices can be employed asactuators or sensors in a variety of micro-electromechanical andmicro-opto-electromechanical applications.

Other features, functions, and aspects of the invention will be evidentfrom the Detailed Description of the Invention that follows.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The invention will be more fully understood with reference to thefollowing Detailed Description of the Invention in conjunction with thedrawings of which:

FIG. 1 is a schematic diagram depicting a piezoelectric morph deviceenergized with a voltage;

FIG. 2a is a side view of a first micro-electromechanical building blockincluding the piezoelectric morph device of FIG. 1, in accordance withthe present invention;

FIG. 2b is a top plan view of the first micro-electromechanical buildingblock of FIG. 2a;

FIG. 3a is a side view of a second micro-electromechanical buildingblock including the piezoelectric morph device of FIG. 1, in accordancewith the present invention;

FIG. 3b is a top plan view of the second micro-electromechanicalbuilding block of FIG. 3a;

FIG. 4a is a side view of a first MEMS device including the first andsecond micro-electromechanical building blocks of FIGS. 2a and 3 a, inaccordance with the present invention;

FIG. 4b is a top plan view of the first MEMS device of FIG. 4a;

FIG. 5a is a side view of a second MEMS device including the secondmicro-electromechanical building block of FIG. 3a, in accordance withthe present invention;

FIG. 5b is a top plan view of the second MEMS device of FIG. 5a;

FIG. 6a is a side view of a third MEMS device, in accordance with thepresent invention;

FIG. 6b is a top plan view of the third MEMS device of FIG. 6a;

FIG. 7a is a side view of a fourth MEMS device including the secondmicro-electromechanical building block of FIG. 3a, in accordance withthe present invention;

FIG. 7b is a top plan view of the fourth MEMS device of FIG. 7a;

FIG. 8 is a top plan view of an optical cross-connect module includingmirrored configurations of the second MEMS device of FIG. 5a, inaccordance with the present invention;

FIG. 9 is a top plan view of a two-morph mirror scanning system, inaccordance with the present invention;

FIG. 10 is a drawing depicting the operation of the mirror scanningsystem of FIG. 9; and

FIG. 11 is a top plan view of a three-morph mirror scanning system, inaccordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The entire disclosure of U.S. patent application Ser. No. 09/700,633filed Nov. 16, 2000 is incorporated herein by reference.

The entire disclosure of U.S. Provisional Patent Application No.60/217,191 filed Jul. 10, 2000 is incorporated herein by reference.

A plurality of MEMS devices is disclosed that can be easily configuredto provide extended ranges of rotational and/or translational motion.The presently disclosed MEMS devices achieve such extended ranges ofmotion by way of a micro-electromechanical building block, at least oneof which can be used to construct a respective MEMS device capable ofmoving a desired angular and/or linear distance.

FIG. 2a depicts a side view of a first micro-electromechanical buildingblock 200 according to the present invention. In the illustratedembodiment, the micro-electromechanical building block 200 includes abendable member 204 having a first end connected to a support structure202, and a straight rigid member 206 having a first end connected to asecond end of the bendable member 204. The straight rigid member 206 isconnected to the bendable member 204 such that when the bendable member204 is in a straight condition, the straight rigid member 206 extendsfrom its connection with the bendable member 204 toward the supportstructure 202.

In a preferred embodiment, the bendable member 204 comprises apiezoelectric bender, which can be made to bend away from a planarposition by applying an electric field across at least one piezoelectriclayer deposited on a surface thereof. For example, the piezoelectricbender 204 may comprise either a “mono-morph” or a “bimorph” (the term“morph” being used to represent either of other equivalent structuresdescribed herein). Further, the micro-electromechanical building block200 is preferably formed from a silicon wafer by a conventional siliconmicro-machining process. Accordingly, the support structure 202comprises a frame of silicon, the bendable member 204 comprises a lengthof silicon having regions with depositions providing bender orpiezoelectric morph functions when energized by an applied voltage, andthe rigid member 206 comprises a rigid silicon bar.

It is understood that the bendable member 204 may alternatively comprisea piezo-magnetic bender that can be made to bend away from a planarposition by application of a magnetic field across at least onepiezo-magnetic layer deposited thereon, or any other type of bender thatcan be made to bend by inducing a stress gradient (via, e.g., anelectric field, a magnetic field, or an application of heat orradiation) along a dimension of the bender.

FIG. 1 depicts a schematic diagram of a piezoelectric bender 104 coupledto a voltage source 108. The piezoelectric bender 104 is representativeof the bendable member 204 included in the micro-electromechanicalbuilding block 200 (see FIG. 2a). Accordingly, when energized by avoltage “V” applied by the voltage source 108, the piezoelectric bender104 provides desired bender or piezoelectric morph functions.

Specifically, the piezoelectric bender 104 comprises a length of siliconhaving a first piezoelectric deposition region 104 a and a secondpiezoelectric deposition region 104 b. When the voltage V is applied bythe voltage source 106, one of the piezoelectric deposition regions 104a or 104 b expands while the other piezoelectric deposition regioncontracts, thereby causing the piezoelectric bender 104 to bend by anamount proportional to the applied voltage, V.

Those of ordinary skill in the art will appreciate that a piezoelectricbimorph energized by an applied voltage is subject to a plurality ofexternal variables including a tip moment “M”, a tip force “F”, apressure “p”, and the applied voltage V. It will also be appreciatedthat canonical conjugates of these four (4) variables are a tip rotation“α”, a tip translation “δ”, a displaced volume “V”, and an electrodecharge “Q”, respectively.

Each of these external variables M, F, p, and V and their respectiveconjugates α, δ, V, and Q are depicted in FIG. 1 relative to thepiezoelectric bender 104. The tip rotation α and the tip translation δare also depicted in FIG. 2a relative to the micro-electromechanicalbuilding block 200 (see also FIGS. 3a, 4 a, 5 a, 6 a, and 7 a).

It should further be appreciated that the tip rotation a is proportionalto the tip translation δ according to the following equation:

α=2δ/L,  (1)

in which “L” is the length of the bendable member 204 (see FIG. 2a).

Accordingly, when the connection between the support structure 202 andthe bendable member 204, as depicted in FIG. 2a, is conceptually placedat the origin of an x-y coordinate system, the bendable member 204extends in the x-direction and deflects in the y-direction. Further, thetangent rigid member 206 connected at the tip of the bendable member 204intersects the x-axis at a distance “L/2” from the origin, andintersects the y-axis at a distance “−δ” from the origin.

Both the bendable member 204 and the tangent rigid member 206 are hereindefined as standard MEMS elements of the micro-electromechanicalbuilding block 200. Specifically, the bendable member 204 and the rigidmember 206 are herein referred to as a bimorph and an “extender”,respectively. Although the extender 206 connected to the bimorph 204 isdepicted in FIG. 2a as pointing in the positive x-direction, it isunderstood that the extender 206 may be suitably connected to thebimorph 204 to allow it to point in the negative x-direction. Theextender 206 pointing in the positive x-direction is herein referred toas a “forward extender”, and the extender 206 pointing in the negativex-direction is herein referred to as a “reverse extender”. Similarly,the bimorph 204 extending in the positive x-direction is herein referredto as a “forward bimorph”, and the bimorph 204 extending in the negativex-direction is herein referred to as a “reverse bimorph”.

Further, although the bimorph 204 is shown in FIG. 2a as bending in thepositive y-direction, it is understood that the bimorph 204 may besuitably configured to bend in the negative y-direction. The forwardbimorph 204 bending in the positive y-direction is herein referred to asa “forward positive bimorph”, and the forward bimorph 204 bending in thenegative y-direction is herein referred to as a “forward negativebimorph”. Similarly, the reverse bimorph 204 bending in the positivey-direction is herein referred to as a “reverse positive bimorph”, andthe reverse bimorph 204 bending in the negative y-direction is hereinreferred to as a “reverse negative bimorph”.

FIG. 2b depicts a top plan view of the micro-electromechanical buildingblock 200. Specifically, the top plan view shows the supportingstructure 202, the forward positive bimorph 204, the reverse extender206, and a suitable silicon micro-machined connector 207 disposedbetween the bimorph 204 and the extender 206. In the illustratedembodiment, the length of the extender 206 is equal to the length L ofthe bimorph 204. The extender 206 having a length equal to that of thebimorph 204 to which it is connected is herein referred to as a “fullextender”.

It is noted that while the free end of the full reverse extender 206intersects the y-axis at the distance −δ from the origin, the midpointof the full reverse extender 206 undergoes rotation, only. This isbecause the midpoint of the full reverse extender 206 is at theequilibrium midpoint of the forward positive bimorph 204.

FIG. 3a depicts a side view of a second micro-electromechanical buildingblock 300 according to the present invention. In the illustratedembodiment, the micro-electromechanical building block 300 includes aforward positive bimorph 304 having a first end connected to a supportstructure 302, and a reverse extender 309 having a first end connectedto a second end of the bimorph 304.

As described above, the midpoint of the full reverse extender undergoespure rotation because it is at the equilibrium midpoint of the forwardpositive bimorph to which it is connected. A top plan view of themicro-electromechanical building block 300 comprising the supportstructure 302, the forward bimorph 304, the reverse extender 309, and asuitable silicon macro-machined connector 307 disposed between thebimorph 304 and the extender 309 (see FIG. 3b) shows that the length ofthe extender 309 is equal to one half the length L of the bimorph 304.Accordingly, the free end of the reverse extender 309 undergoes purerotation because it is at the equilibrium midpoint of the forwardpositive bimorph 304.

Both the forward bimorph 304 and the reverse extender 309 are hereindefined as standard MEMS elements of the micro-electromechanicalbuilding block 300. It is noted that the extender 309 having a lengthequal to one half that of the bimorph 304 to which it is connected isherein referred to as a “half extender”.

Although the micro-electromechanical building block 200 includes thefull reverse extender 206 (see FIG. 2a), and the micro-electromechanicalbuilding block 300 includes the half reverse extender 309 (see FIG. 3a),it is understood that each of the extenders 206 and 309 mayalternatively have a respective length at least within a range from onehalf to the full length of the bimorph connected thereto to allow thefree end of the extender to undergo a desired rotational and/ortranslational motion.

The standard MEMS elements of the micro-electromechanical buildingblocks 200 and 300 can be connected to each other in variouscombinations to construct MEMS devices capable of moving desired angularand/or linear distances.

FIG. 4a depicts a side view of a first MEMS device 400 constructed usinga combination of the standard MEMS elements of themicro-electromechanical building blocks 200 and 300 (see FIGS. 2a and 3a), in accordance with the present invention. Further, FIG. 4b depicts atop plan view of this first MEMS device 400, which is constructed toundergo a pure rotation α at the tip of a half reverse extender 412.

In the illustrated embodiment, the first MEMS device 400 includes aforward positive bimorph 404 having a first end connected to a supportstructure 402, a full reverse extender 406 having a first end connectedto a second end of the forward positive bimorph 404, a forward positivebimorph 410 having a first end connected to a second end of the fullreverse extender 406, and the half reverse extender 412 having a firstend connected to a second end of the forward positive bimorph 410.

It is noted that the combination of the forward positive bimorph 404 andthe full reverse extender 406 conforms to the general configuration ofthe micro-electromechanical building block 200 (see FIG. 2a), and thecombination of the forward positive bimorph 410 and the half reverseextender 412 conforms to the general configuration of themicro-electromechanical building block 300 (see FIG. 3a).

Moreover, the net result of the bending forward positive bimorph 404 andits connection to the full reverse extender 406, and the bending forwardpositive bimorph 410 and its connection to the half reverse extender 412is that the tip of the half reverse extender 412 undergoes a rotation awithout translation.

FIG. 5a depicts a side view of a second MEMS device 500 constructedusing the standard MEMS elements of the micro-electromechanical buildingblocks 200 and 300 (see FIGS. 2a and 3 a), in accordance with thepresent invention. Further, FIG. 5b depicts a top plan view of thissecond MEMS device 500, which is constructed to undergo a puretranslation δ at the tip of a forward negative bimorph 514.

In the illustrated embodiment, the second MEMS device 500 includes aforward positive bimorph 504 having a first end connected to a supportstructure 502, a half reverse extender 512 having a first end connectedto a second end of the forward positive bimorph 504, and the forwardnegative bimorph 514 having a first end connected to a second end of thehalf reverse extender 512.

It is noted that the combination of the forward positive bimorph 504 andthe half reverse extender 512 conforms to the general configuration ofthe micro-electromechanical building block 300 (see FIG. 3a).

Moreover, the net result of the bending forward positive bimorph 504 andits connection to the half reverse extender 512, and the bending forwardnegative bimorph 514 is that the tip of the forward negative bimorph 514undergoes a translation δ without rotation. The construction of thissecond MEMS device 500 is herein referred to as a “single deltatranslator”.

FIG. 6a depicts a side view of a third MEMS device 600 constructed usingthe standard MEMS elements of the micro-electromechanical buildingblocks 200 and 300 (see FIGS. 2a and 3 a), in accordance with thepresent invention. Further, FIG. 6b depicts a top plan view of thisthird MEMS device 600, which is constructed to undergo an extended rangeof pure translational motion 2δ at the tip of a forward negative bimorph614.

In the illustrated embodiment, the third MEMS device 600 includes aforward positive bimorph 604 having a first end connected to a supportstructure 602, and the forward negative bimorph 614 having a first endconnected to a second end of the forward positive bimorph 604.

Moreover, the net result of the bending forward positive bimorph 604 andthe bending forward negative bimorph 614 is that the tip of the forwardnegative bimorph 614 undergoes an extended translation 2δ withoutrotation. The construction of this third MEMS device 600 is hereinreferred to as a “double delta translator”.

FIG. 7a depicts a side view of a fourth MEMS device 700 constructedusing the standard MEMS elements of the micro-electromechanical buildingblocks 200 and 300 (see FIGS. 2a and 3 a), in accordance with thepresent invention. Further, FIG. 7b depicts a top plan view of thisfourth MEMS device 700, which is constructed to undergo a puretranslation δ at the tip of a half forward extender 716.

In the illustrated embodiment, the fourth MEMS device 700 includes aforward negative bimorph 704 having a first end connected to a supportstructure 702, a half reverse extender 712 having a first end connectedto a second end of the forward negative bimorph 704, a reverse negativebimorph 714 having a first end connected to a second end of the halfreverse extender 712, and the half forward extender 716 having a firstend connected to a second end of the reverse negative bimorph 714.

Moreover, the net result of the bending forward negative bimorph 704 andits connection to the half reverse extender 712, and the bending of thereverse negative bimorph 714 and its connection to the half reverseextender 716 is that the tip of the half reverse extender 716 undergoesa translation δ without rotation. The construction of this fourth MEMSdevice 700 therefore comprises another single delta translator.

It is noted that the standard MEMS elements of themicro-electromechanical building blocks 200 and 300 and/or the first,second, third, or fourth MEMS devices 400, 500, 600, or 700 may besuitably stacked to form higher order rotators and translators. Further,in order to avoid twisting moments, these constructions can be madesymmetrical by mirroring them. For example, a translator may be formedin which a MEMS device and its mirrored counterpart provide a connectionto a structure comprising an optical surface (e.g., an optical mirror, aprism, or an optical grating—either transparent or reflective) such thatthe tip of the last MEMS element of the translator is allowed to undergoa desired translational motion with no twisting moments.

FIG. 8 depicts an optical cross-connect module 800 according to thepresent invention. In the illustrated embodiment, the opticalcross-connect module 800 includes a switching unit 802 comprising anoptical mirror positioned on a platform 804, which is connected to three(3) sets of double delta translators 806, 808, and 810 positioned atangles of about 120° from each other. Specifically, the double deltatranslator 806 is formed by mirroring a stack comprising the second MEMSdevice 500 connected between two (2) micro-electromechanical buildingblocks 200. The double delta translators 808 and 810 are formed in asimilar manner. Accordingly, when the double delta translators 806, 808,and 810 are energized with suitable applied voltages, the platform 804is raised (lowered) to insert (remove) the optical mirror in (from) thepath of light beams emitted from optical fiber ports (not shown).

It is noted that the raising (lowering) of the platform 804 mayalternatively be achieved by employing more than one set of single,double, triple, or higher order translators.

FIG. 9 depicts a top plan view of a two-morph mirror scanning system 900according to the present invention. In the illustrated embodiment, thetwo-morph mirror scanning system 900 includes a mirrored siliconplatform or area 10 supported and etch-released from a silicon frame 12by respective silicon support arms 14 and 16. Overlying the arms 14 and16 are respective morphs 18 and 20 that may be mono-morphs or bimorphs.The morphs 18 and 20 comprise piezoelectric depositions formed duringthe silicon micro-machining of the device. In their configurations asbenders, the morphs 18 and 20 have upper and lower electricalconnections 22 and 24 to terminals 26, each formed as a metalization onthe frame 12. It is noted that the frame 12 is merely shownschematically, and typically would be of greater extent in bothdirections of the plane of the page.

FIG. 10 depicts a diagrammatic illustration of the principle ofoperation of the two-morph mirror scanning system 900 according to thepresent invention, in which a mirror 10′ is supported on arms 14′ and16′ within a frame 12′. As the morphs or bimorphs of the arms 14′ and16′ are electrically actuated to bend in opposite directions, the mirror10′ can be tilted a considerable distance. By varying and controllingthe signals applied to the morphs, the degree of bending and the angleof inclination of the mirror 10′ can be precisely set or scanned withknowledge of the exact position of the mirror. For this purpose, thesystem of the invention is normally operated with a microprocessor orother processor 28 (see FIG. 9), which controls the magnitude of thesignals applied to terminals 26 with or without interfacing drivers 30(see FIG. 9).

It is noted that the respective combinations of the arm 14′ and themirror 10′, and the arm 16′ and the mirror 10′, conform to the generalconfiguration of the micro-electromechanical building block 200 (seeFIG. 2a). Further, because the midpoint of the mirror 10′ is at therespective equilibrium midpoints of the arms 14′ and 16′, the midpointof the mirror 10′ undergoes rotation without translation. The midpointof the mirror 10′ therefore comprises the axis of rotation of the mirror10′.

FIG. 11 depicts a further embodiment of the present invention, in whichthree “J” shaped arms 1100, completing nearly a 180° curvature andangled at 120° from each other, are supported from the edge 1102 of aframe. The initial linear portion 1104 of the arms 1100 is plated tofunction as morphs or benders. A computation system 1106 drives themorphs and accomplishes any coordinate transformations necessary toadjust orthogonal drive signals to the 120° angles. A mirror 1110 isformed in the center, as described above.

Stress relief structures 1112 are formed of silicon between the ends ofthe arms 1100 and the mirror 1108 to accommodate a difference in slopebetween the sides of the arms 1100 at the juncture with the mirror dueto the substantial curving of the arms 1100 at the end and the 120° armplacement. The stress relief structures 1112 comprise a widening of thearms with the centers etched out leaving only outer bands for theattachment over a few degrees of curvature. In a preferred embodiment,the midpoint of the initial linear portion 1104 of each of the three (3)arms 1100 is in line with the stress relief structures 1112 of theremaining two (2) arms 1100. In this configuration, the arms 1100 cancause the mirror 1108 to move with minimal stress and inertia.

Of particular advantage to such a structure is the fact that if themorphs or benders on the arm portions 1104 are electrically driven tobend in the same direction by an identical amount, or nearly so, themirror 1110 is given a bending moment at its edges where the armsattach. This results in the mirror 1110 being bent slightly in a convexor concave shape, which has usefulness in providing focusing ordefocusing effects on light beams reflected thereby.

Although “bimorphs” and “extenders” are herein described as distinctstandard MEMS elements of the micro-electromechanical building blocks200 and 300 (see FIGS. 2a and 3 a), it should be understood that abimorph may be configured to act as a bender and/or an extender. Forexample, by applying suitable voltages to a bimorph, the bimorph can betransformed from a positive/negative bimorph to an extender and from theextender back to the positive/negative bimorph.

Moreover, even though the micro-electromechanical building blocks 200and 300 (see FIGS. 2a and 3 a) are herein described as including a fullreverse extender and a half reverse extender, respectively, it isunderstood that the building blocks 200 and 300 may alternativelyinclude respective reverse extenders having any desired length, so longas the reverse extenders are disposed internal to the area of therespective bimorphs. Similarly, an optical surface such as the opticalsurface 10′ (see FIG. 10) may have any desired length so long as it isdisposed internal to the area of the arm 14′ or 16′. For example, abimorph suitably connected at one end to an optical surface conformingto the general configuration of a “quarter reverse extender” may beemployed to implement an optical grating.

It will further be appreciated by those of ordinary skill in the artthat modifications to and variations of the above-described devices andmethods may be made without departing from the inventive conceptsdisclosed herein. Accordingly, the invention should not be viewed aslimited except as by the scope and spirit of the appended claims.

What is claimed is:
 1. A micro-electromechanical building block forconstructing a micro-electromechanical device, comprising: at least onebendable member having a first end connectable to a support structureand a predetermined length; and at least one straight rigid memberhaving a first end connected to a second end of the respective bendablemember, the rigid member extending toward the support structure in theevent the respective bendable member is in a straight condition, whereinthe rigid member has a length less than or equal to the predeterminedlength of the bendable member to allow a free end of the rigid member toundergo motion ranging from a pure rotation, a combined rotation andtranslation, to a pure translation in response to a displacement of therespective bendable member.
 2. A micro-electromechanical device,comprising: the micro-electromechanical building block of claim 1,wherein the rigid member has a length equal to one half thepredetermined length of the bendable member to allow the free end of therigid member to undergo a pure rotation in response to a displacement ofthe bendable member.
 3. A micro-electromechanical device, comprising: afirst micro-electromechanical building block according to claim 1, thefirst building block including a first bendable member having a firstpredetermined length and a first rigid member, wherein the first rigidmember has a length equal to the first predetermined length; and asecond micro-electromechanical building block according to claim 1, thesecond building block including a second bendable member having a secondpredetermined length and a second rigid member, wherein the second rigidmember has a length equal to one half the second predetermined length,wherein the free end of the first rigid member is connected to the firstend of the second bendable member to allow the free end of the secondrigid member to undergo a pure rotation in response to a displacement ofat least the first bendable member.
 4. A micro-electromechanical device,comprising: a micro-electromechanical building block according to claim1, the building block including a first bendable member having a firstpredetermined length and a rigid member having a length equal to onehalf the first predetermined length; and a second bendable memberconnected to the free end of the rigid member to allow a free end of thesecond bendable member to undergo a pure translation in response to adisplacement of at least the first bendable member.
 5. Amicro-electromechanical device, comprising: a first bendable memberhaving a first end connectable to a support structure and apredetermined length; and a second bendable member having a first endconnected to a second end of the first bendable member and extendingaway from the support structure in the event the first and secondbendable members are in respective straight conditions, the secondbendable member having a length equal to the predetermined length of thefirst bendable member, wherein the first and second bendable members areconfigured to undergo respective displacements in opposite directions toallow a free end of the second bendable member to undergo a puretranslation in response to a displacement of at least the first bendablemember.
 6. A micro-electromechanical device, comprising: a firstmicro-electromechanical building block according to claim 1, the firstbuilding block including a first bendable member having a firstpredetermined length and a first rigid member having a length equal toone half of the first predetermined length; and a secondmicro-electromechanical building block according to claim 1, the secondbuilding block including a second bendable member having a secondpredetermined length and a second rigid member having a length equal toone half of the second predetermined length, wherein the free end of thefirst rigid member is connected to the first end of the second bendablemember to allow the free end of the second rigid member to undergo apure translation in response to a displacement of at least the firstbendable member.
 7. A micro-mechanical system of one or more platformsand plural supports wherein at least one platform is configured to havean optical surface, the system comprising: a frame configured to holdone or more of the plural supports at respective ends thereof distantfrom a corresponding platform; and a plurality of morph driverscoextensive and associated with a portion of respective ones of aplurality of the plural supports, wherein remaining portions of theplural supports are angled to the portion to which the morphs arecoextensive.
 8. The system of claim 7 wherein a first plurality of thesupports extends from the frame to a first platform and a secondplurality of the supports extends from the frame to a second platform,the first and second pluralities of supports having morph driversassociated therewith, and a third plurality of the supports extends fromthe first and second platforms to a third platform, the third platformbeing adapted for an optical surface.
 9. The system of claim 7 whereinthe supports are configured for substantially forming a right angle. 10.The system of claim 9 wherein the supports number three in total,oriented at about 120 degrees from each other.
 11. The system of claim 7wherein a strain-relieving configuration is provided to connect thesupports and the platforms.
 12. The system of claim 7 further includingelectrical connections to the morphs from terminals on the frameconfigured to provide bending of the supports in different directions inresponse to a signal applied to the terminals.
 13. The system of claim 7further including electrical connections to the morphs from terminals onthe frame configured to provide tilting of the platform in differentdirections in response to a signal applied to the terminals.
 14. Thesystem of claim 7 further including electrical connections to the morphsfrom terminals on the frame configured to provide bending of theplatform in a convex or concave shape in response to a signal applied tothe terminals.
 15. The system of claim 7 wherein the supports comprisemultiple arms selected from the group consisting of arms with morphs ofa selected length and arms without morphs of a selected length.
 16. Thesystem of claim 7 wherein the supports and the platforms are made ofsilicon.
 17. The system of claim 15 wherein the supports and theplatforms are etch-released from the frame.
 18. The system of claim 7wherein the morphs are selected from the group consisting of mono-morphsand bimorphs.
 19. The system of claim 7 wherein the morphs arepiezoelectric elements applied to the supports.
 20. A method forcontrolling a pointing angle of a light reflecting element, comprisingthe steps of: providing a system as claimed in claim 1; and applyingsignals to morphs of the system from a processor to produce angulationof the light reflecting element.
 21. The method of claim 20 wherein theprocessor provides a coordinate transformation.
 22. The method of claim20 wherein the light reflecting element includes a mirror.
 23. A methodof forming a scanning system, comprising the steps of: forming amicro-mechanical system of claim 7 from silicon.
 24. The method of claim23 further including forming the morphs as layered piezoelectricelements on silicon supports between the frame and the reflectingelement.
 25. The system of claim 9 wherein at least one platform takeson a convex or concave shape under the influence of a similar bending ofthe morphs.
 26. A method for adjusting a focusing effect of the opticalsurface of claim 7, comprising the steps of: causing the morphs to bendin substantially the same direction and magnitude to apply a bendingmoment to edges of the optical surface, thereby causing a bendingthereof in a convex or concave shape.
 27. A method for adjusting afocusing effect of the optical surface of claim 7, comprising the stepsof: causing the morphs to bend in respective directions and magnitudesto tilt the optical surface in a plurality of directions.